As DWDM system is composed of these five components, how do they work together? The following steps give out the answer (also you can see the whole structure of a fundamental DWDM system in the figure below):
1. The transponder accepts input in the form of a standard single-mode or multimode laser pulse. The input can come from different physical media and different protocols and traffic types.
2. The wavelength of the transponder input signal is mapped to a DWDM wavelength.
3. DWDM wavelengths from the transponder are multiplexed with signals from the direct interface to form a composite optical signal which is launched into the fiber.
4. A post-amplifier (booster amplifier) boosts the strength of the optical signal as it leaves the multiplexer.
5. An OADM is used at a remote location to drop and add bitstreams of a specific wavelength.
6. Additional optical amplifiers can be used along the fiber span (in-line amplifier) as needed.
7. A pre-amplifier boosts the signal before it enters the d e muliplexer.
8. The incoming signal is demultiplexed into individual DWDM wavelengths.
9. The individual DWDM lambdas are either mapped to the required output type through the transponder or they are passed directly to client-side equipment.
DWDM System Structure
Using DWDM technology, DWDM systems provide the bandwidth for large amounts of data. In fact, the capacity of DWDM systems is growing as technologies advance that allow closer spacing, and therefore higher numbers, of wavelengths. But DWDM is also moving beyond transport to become the basis of all-optical networking with wavelength provisioning and mesh-based protection. Switching at the photonic layer will enable this evolution, as will the routing protocols that allow light paths to traverse the network in much the same way as virtual circuits do today. With the development of technologies, DWDM systems may need more advanced components to exert greater advantages.